Medical image processing apparatus

ABSTRACT

According to one embodiment, an ultrasonic diagnostic apparatus includes a transmission/reception circuit and processing circuitry. The transmission/reception circuit performs a first scan and a second scan, which are different in acoustic field in an elevation direction, by controlling at least one of transducers arranged along an azimuth direction and the elevation direction. The processing circuitry generates a first needle-enhanced image by using data acquired in the first scan, and generates a second needle-enhanced image by using data acquired in the second scan.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of Japanese PatentApplication No. 2016-074539, filed Apr. 1, 2016, and Japanese PatentApplication No. 2017-034521, filed Feb. 27, 2017, the entire contents ofall of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to an ultrasonicdiagnostic apparatus and an ultrasonic image generation method.

BACKGROUND

Ultrasonic images imaged by an ultrasonic diagnostic apparatus are usedfor monitoring in paracentesis in some cases. In such cases, it ispreferable to display both of a B-mode image and a needle-enhanced imagein which a puncture needle is emphasized, because the B-mode image iseffective for confirming a body tissue and the needle-enhanced image iseffective for confirming a position of the puncture needle.

As a method of generating a needle-enhanced image, there is a knownmethod of performing a scan for generating a needle-enhanced image(hereinafter, referred to as a needle-enhanced scan) aside from a scanfor generating a body-tissue image (hereinafter, referred to as abody-tissue scan) and displaying a composite image of a needle-enhancedimage and a body-tissue image such as a B-mode image. However, when apuncture needle is displaced from an acoustic field (hereinafter, such astate is referred to as an off-plane state), each echo signal from thepuncture needle is weakened and visibility of the puncture needle isreduced.

As a technique of improving visibility of a puncture needle in such atype of off-plane state, there is a technique of widening width of anacoustic field in the elevation direction in a needle-enhanced scan morethan that in a body-tissue scan by using an ultrasonic probe in whichplural ultrasonic transducers are arranged in the elevation direction.According to this kind of technique, even if a puncture needle is in theoff-plane state with respect to an acoustic field of a body-tissue scan,an ultrasonic probe can receive echo signals of strong intensity fromthis puncture needle when the puncture needle is positioned within anacoustic field of a needle-enhanced scan.

However, when width of an acoustic field of a needle-enhanced scan inthe elevation direction is widened, a reception beam does notsufficiently converge, which blurs a puncture needle depicted in aneedle-enhanced image. Further, in this case, a B-mode image and aneedle-enhanced image have different imaging region. Thus, when acomposite image of a body-tissue image and a needle-enhanced image aregenerated and displayed, it will be difficult for a user to recognizethe actual position of the puncture needle spatially separated from thebiological cross-section of the body-tissue image, which may sometimesimpair the safety and reliability of medical treatment.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 is a block diagram illustrating a configuration of the ultrasonicdiagnostic apparatus according to the first embodiment of the presentinvention;

FIG. 2 is a schematic plan view illustrating arrangement of ultrasonictransducers constituting an ultrasonic probe;

FIG. 3 is a general block diagram illustrating functions implemented bya processor of processing circuitry;

FIG. 4 is a flowchart illustrating processing performed by the processorof the processing circuitry in order to assist a user in easilyunderstanding positional relationship between a puncture needle and abiological cross-section corresponding to a body-tissue image;

FIG. 5A is a schematic diagram illustrating a position of a punctureneedle in relation to a transmission/reception direction of ultrasonicwaves in a B-mode scan;

FIG. 5B is a schematic diagram illustrating a position of the punctureneedle in relation to the transmission/reception direction of ultrasonicwaves in a needle-enhanced scan;

FIG. 6A is a schematic diagram illustrating a narrow acoustic field in anarrow-field needle-enhanced scan; FIG. 6B is a schematic diagramillustrating a wide acoustic field in a wide-field needle-enhanced scan;

FIG. 7 is a schematic diagram illustrating relationship between apuncture support image generated by combining a narrow-fieldneedle-enhanced image with a wide-field needle-enhanced image in theoff-plane state, a narrow acoustic field, and a wide acoustic field; and

FIG. 8 is a schematic diagram illustrating a puncture support image anda composite image.

DETAILED DESCRIPTION

Hereinbelow, a description will be given of an ultrasonic diagnosticapparatus and an ultrasonic image generation method according toembodiments of the present invention with reference to the drawings. Anultrasonic diagnostic apparatus according to one embodiment of thepresent invention may be used when paracentesis is performed underguidance of ultrasonic images for example.

In general, according to one embodiment, an ultrasonic diagnosticapparatus includes a transmission/reception circuit and processingcircuitry. The transmission/reception circuit performs a first scan anda second scan, which are different in acoustic field in an elevationdirection, by controlling at least one of transducers arranged along anazimuth direction and the elevation direction. The processing circuitrygenerates a first needle-enhanced image by using data acquired in thefirst scan, and generates a second needle-enhanced image by using dataacquired in the second scan.

FIG. 1 is a block diagram illustrating a configuration of the ultrasonicdiagnostic apparatus 10 of the present embodiment. The ultrasonicdiagnostic apparatus 10 includes an ultrasonic probe 11, a punctureneedle 12, an operation panel 20, a display 30, and a main body 40.

FIG. 2 is a schematic plan view illustrating arrangement of ultrasonictransducers constituting the ultrasonic probe 11. The ultrasonic probe11 is equipped with plural ultrasonic transducers (piezoelectricvibrators). Each of those plural ultrasonic transducers generates anultrasonic wave based on a drive signal supplied from the main body 40.The ultrasonic probe 11 transmits ultrasonic waves generated by theultrasonic transducers to inside of a body of an object P, and receivesecho signals from the object P so as to convert the echo signals intoelectric signals. Moreover, the ultrasonic probe 11 includes componentssuch as a matching layer provided on the ultrasonic transducers and abacking material which prevents ultrasonic waves from propagating towardthe back side of the ultrasonic transducers.

In the present embodiment, the ultrasonic probe 11 is configured to beable to perform the first and second scans which are different inacoustic field in the elevation direction (also referred to as the slicedirection) from each other. Thus, a two-dimensional array probe in whichplural transducers are arranged in the elevation direction can be usedas the ultrasonic probe 11. As such a type of two-dimensional arrayprobe, a 1.5-dimensional array probe, a 1.75-dimensional array probe,and a two-dimensional array probe can be used for example.

The above-described 1.5-dimensional array probe is such a probe thattransducers equidistant from the center in the elevation direction areconnected with each other (FIG. 2), an acoustic field of an ultrasonicwave is symmetric along the elevation direction about the center axis,and delay of transmitted/received ultrasonic waves and apodization canbe controlled so as to be symmetric about the center axis in theelevation direction.

The above-described 1.75-dimensional array probe is such a probe thatits aperture is variable in the elevation direction, its focal lengthcan be dynamically changed, and an acoustic field of an ultrasonic wavein the elevation direction can be asymmetric about the center axis.

The above-described two-dimensional array probe is such a probe thattransmission/reception signal lines of respective transducers areindependent of each other, and delay of transmitted/received ultrasonicwaves, apodization, the acoustic field center, and atransmission/reception angle can be controlled in the elevationdirection. In the following, a case where a 1.5-dimensional array probeis used as the ultrasonic probe 11 will be described.

The puncture needle 12 is mounted on the ultrasonic probe 11 via a guideattachment or the like, and is punctured into a predetermined part ofthe object P by a user.

The operation panel 20 functions as a touch command screen, and includesa display, a touch input circuit disposed beside this display, and ahardware key 22. The touch input circuit provides the main body 40 withinformation on an instruction position on a touch input circuit touchedby a user. A keyboard, a mouse, a foot switch, a track ball, varioustypes of buttons and the like can be used as the hardware key 22. Thetouch input circuit and the hardware key integrally constitute an inputcircuit which receives various types of commands from a user of theultrasonic diagnostic apparatus 10.

The display 30 is configured of a general display output device such asa liquid crystal display and an OLED (Organic Light Emitting Diode)display, and display an ultrasonic image such as a composite image of abody-tissue image and a puncture support image generated by the mainbody 40. Additionally, the display 30 displays an image for a user ofthe ultrasonic diagnostic apparatus 10 to input various types ofcommands with the use of the operation panel 20. Further, the display 30displays notification information for a user received from the main body40.

The main body 40 generates an ultrasonic image based on an echo signalfrom the object P received by the ultrasonic probe 11. As shown in FIG.1, the main body 40 includes a transmission/reception circuit 50, aB-mode processing circuit 51, a Doppler processing circuit 52, an imagegeneration circuit 53, an image memory 54, a timer 55, memory circuitry56, processing circuitry 57, and a display control circuit 58.

The transmission/reception circuit 50 includes a transmitting circuit 50a and a receiving circuit 50 b, and controls transmission directivityand reception directivity in transmission and reception of ultrasonicwaves in cooperation with the processing circuitry 57. Although adescription has been given of a case where the transmission/receptioncircuit 50 is provided on the main body 40 in FIG. 1, thetransmission/reception circuit 50 may be provided on the ultrasonicprobe 11 or may be provide on both the ultrasonic probe 11 and the mainbody 40.

The transmitting circuit 50 a includes a pulse generator, a transmissiondelay circuit, and a pulsar circuit, and supplies the ultrasonic probe11 with a driving signal. The pulse generator repeatedly generates arate pulse for forming an ultrasonic wave to be transmitted at apredetermined rate frequency. The transmission delay circuit diffuses orfocuses an ultrasonic wave generated from the ultrasonic probe 11 into abeam and provides, to each rate pulse generated by the pulse generator,a delay time per ultrasonic transducer that is necessary to determinethe transmission directionality. Additionally, the pulsar circuitapplies a driving pulse to the ultrasonic probe 11 at a timing based oneach rate pulse. The transmission delay circuit changes the delay timeprovided to each rate pulse so as to appropriately adjust a transmissiondirection of an ultrasonic wave in which the ultrasonic wavestransmitted from the surface of the ultrasonic transducers istransmitted.

Further, in order to execute a predetermined scan sequence under thecontrol of the processing circuitry 57, the transmitting circuit 50 ahas a function of instantaneously changing parameters such as atransmission frequency and a transmission driving voltage. The functionof changing a transmission driving voltage is implemented by a linearamplifier type of oscillator capable of instantaneously changing thevalue of the transmission driving voltage or a structure of electricallyswitching plural power-supply units.

The receiving circuit 50 b includes an amplifier circuit, an A/Dconverter, and an adder circuit. The receiving circuit 50 b receivesecho signals received by the ultrasonic probe 11 and generates reflectedwave data by performing various types of processing on the echo signals.The amplifier circuit performs gain correction processing by amplifyingthe echo signals for each channel. The A/D converter performs A/Dconversion on the reflected wave signals subjected to the gaincorrection processing, and provides the digitized data with a delay timenecessary for determining reception directivity. The adder circuitperforms addition processing of the echo signals digitized by the A/Dconverter so as to generate reflected wave data. Each reflectedcomponent from a direction according to reception directivity of eachecho signal is enhanced by the addition processing of the adder circuit.

The B-mode processing circuit 51 receives reflected wave data from thereceiving circuit 50 b and performs logarithmic amplification, envelopedetection on the reflected wave data, and the like, so as to generate(B-mode) data expressing the signal intensity by luminance brightness.

The Doppler processing circuit 52 performs frequency analysis onvelocity information from the reflected wave data received from thereceiving circuit 50 b, and extracts a blood-flow component, a tissuecomponent, and a contrast-agent echo component by the Doppler effect. Inthis manner, the Doppler processing circuit 52 generates Doppler data inwhich moving-object information items such as the average velocity,variance, and power are extracted for multiple points.

The image generation circuit 53 generates an ultrasonic image based onreflected waves received by the ultrasonic probe 11. Specifically, theimage generation circuit 53 generates an ultrasonic image from datagenerated by the B-mode processing circuit 51 and the Doppler processingcircuit 52. For instance, the image generation circuit 53 generates aB-mode image in which intensity of each reflected wave is indicated bybrightness based on two-dimensional B-mode data generated by the B-modeprocessing circuit 51.

Additionally, the image generation circuit 53 generates a color Dopplerimage indicative of moving-object information from two-dimensionalDoppler data generated by the Doppler processing circuit 52. Such acolor Doppler image is generated as an average velocity image, avariance image, a power image, or a combination image of these images.In the following description, an ultrasonic image such as atwo-dimensional B-mode image and a two-dimensional color Doppler imageis arbitrarily referred to as a body-tissue image.

In general, the image generation circuit 53 converts signal lines ofrespective ultrasonic scanlines into scanning signal lines of a videoformat typified by a television format so as to generate atwo-dimensional ultrasonic image for display. Specifically, the imagegeneration circuit 53 generates a two-dimensional ultrasonic image to bedisplayed by performing coordinate conversion according to the mode ofscanning using ultrasound performed by the ultrasonic probe 11.

The image memory 54 is a memory circuit configured to store data ofultrasonic images generated by the image generation circuit 53 such as aB-mode image and a color Doppler image.

The timer 55 is controlled by the processing circuitry 57, and isactivated by setting a predetermined time. For instance, assuming that athreshold value Tth is set to the timer 55 and the timer 55 is activatedso as to start time-count, the timer 55 outputs a time-out signal andstops time-count when the timer threshold value Tth elapses after thestart of time-count.

The memory circuitry 56 is equipped with a configuration includingmemory media which can be read by a processor such as a magnetic memorymedium, an optical memory medium, and a semiconductor memory. The memorycircuitry 56 may be configured such that some or all of the programs anddata stored in those memory media can be downloaded by means ofcommunication via an electronic network.

The processing circuitry 57 is a processor configured, by executingprograms, to execute processing for a user to easily understandpositional relationship between the puncture needle 12 and a biologicalcross-section corresponding to a body-tissue image.

The display control circuit 58 includes a GPU (Graphics Processing Unit)and a VRAM (Video Random Access Memory). The display control circuit 58causes the display 30 to display an image which is requested to bedisplayed by the processing circuitry 57, under the control of theprocessing circuitry 57. The display control circuit 58 may display animage, which is substantially equivalent to the image displayed on thedisplay 30, on the display of the operation panel 20.

FIG. 3 is a general block diagram illustrating functions implemented bythe processor of the processing circuitry 57. As shown in FIG. 3, theprocessor of the processing circuitry 57 implements a scan controlfunction 61, an image generation function 62, a state determinationfunction 63, and a notification function 64. The respective functions 61to 64 are stored in the form of programs in the memory circuitry 56.

First, outlines of functions 61 to 64 will be described.

The scan control function 61 and the transmission/reception circuit 50integrally constitute a scan unit 70. The scan unit 70 performs thefirst and second scans being different in acoustic field in theelevation direction from each other, by controlling at least one of theplural ultrasonic transducers of the ultrasonic probe 11 arranged alongthe azimuth direction and the elevation direction. The scan controlfunction 61 controls the transmission/reception circuit 50 so as tocause the transmission/reception circuit 50 to perform the first andsecond scans which are different in acoustic field in the elevationdirection from each other.

The image generation function 62 generates the first needle-enhancedimage from ultrasonic data acquired in the first scan, and generates thesecond needle-enhanced image from ultrasonic data acquired in the secondscan. Additionally, the image generation function 62 generates apuncture support image as puncture support information by composing thefirst needle-enhanced image with the second needle-enhanced image.Further, the image generation function 62 generates a body-tissue imagefrom ultrasonic data acquired in a body-tissue scan, and generates acomposite image of this body-tissue image and the puncture support imageso as to cause the display 30 to display the composite image.

Moreover, the image generation function 62 may have a mode in which oneof the first needle-enhanced image and the second needle-enhanced imageis displayed on the display 30 (hereinafter, referred to as a switchingmode). In the switching mode, an image to be displayed on the display 30may be switched from one of the first and second needle-enhanced imagesto the other in an automatic manner according to setting of theultrasonic diagnostic apparatus 10 or in a manual manner according to aninstruction from a user.

The state determination function 63 determines whether the punctureneedle 12 is displaced from an acoustic field of a body-tissue scan ornot (i.e., whether it is in the off-plane state or not). For instance,the state determination function 63 determines to be in the off-planestate when a predetermined ratio is not lower than a ratio obtained bydividing the number of pixels of the first needle-enhanced image whosepixel values are equal to or higher than a predetermined pixel value bythe number of pixels of the second needle-enhanced image whose pixelvalues are equal to or higher than a predetermined pixel value.

When the state determination function 63 determines that it is in theoff-plane state, the notification function 64 outputs puncture supportinformation indicating that it is in the off-plane state. Specifically,when the state determination function 63 determines to be in theoff-plane state, the notification function 64 notifies a user of beingin the off-plane state by causing the display 30 to display an imageindicative of being in the off-plane state or causing a non-illustratedspeaker to output sound such as voice or a beep indicative of the same.

Plural scans being different in acoustic field in the elevationdirection from each other are performed for generating the puncturesupport image, and plural scans can be three or more scans.

In the following, a description will be given of a case where two scans,i.e., the first scan and the second scan, are performed for generatingthe puncture support image. Additionally, out of the first scan and thesecond scan, the one which is narrower in width of an acoustic field inthe elevation direction is referred to as a narrow-field needle-enhancedscan, and the other is referred to as a wide-field needle-enhanced scan.

Next, details of the respective functions 61 to 64 will be describedwith reference to FIG. 4 to FIG. 8.

FIG. 4 is a flowchart illustrating processing performed by the processorof the processing circuitry 57 in order to assist a user in easilyunderstanding positional relationship between the puncture needle 12 anda biological cross-section corresponding to a body-tissue image. In FIG.4, each reference sign composed of S and number on its right sideindicates step number of the flowchart.

Further, in FIG. 4, a description will be given of a case where thenarrow acoustic field 81 is equal to an acoustic field of a body-tissuescan, i.e., the narrow acoustic field 81 is equal to a biologicalcross-section corresponding to a body-tissue image.

First, in the step S1, the scan unit 70 sets width of an acoustic fieldin the elevation direction to predetermined width, and then performs abody-tissue scan. The image generation function 62 generates abody-tissue image based on an echo signal acquired by the body-tissuescan. It is preferable that the predetermined width of an acoustic fieldused in the body-tissue scan has a value corresponding to a sufficientlyfocused ultrasonic beam in order to make a body-tissue image as clearlyas possible.

Next, in the step S2, the scan unit 70 performs a narrow-fieldneedle-enhanced scan. Then, the image generation function 62 generates anarrow-field needle-enhanced image based on an echo signal acquired bythe narrow-field needle-enhanced scan. It is preferable that width of anacoustic field in the elevation direction used in the narrow-fieldneedle-enhanced scan is substantially the same as the above-describedpredetermined width of an acoustic field used in the body-tissue scan.

Here, a method of generating a puncture support image in the off-planestate will be described.

FIG. 5A is a schematic diagram illustrating a position of the punctureneedle 12 in relation to a transmission/reception direction ofultrasonic waves in the B-mode scan. FIG. 5B is a schematic diagramillustrating a position of the puncture needle 12 in relation to atransmission/reception direction of ultrasonic waves in theneedle-enhanced scan. The term “needle-enhanced scan” is assumed to be acollective term of scans performed for generating a puncture supportimage such as the first scan and the second scan. Additionally, each ofFIG. 5A and FIG. 5B illustrates a case where the ultrasonic probe 11 isa linear type.

The puncture needle 12 is not necessarily vertically punctured withrespect to a body surface of the object P. Thus, as shown in FIG. 5A, inthe B-mode scan as an example of a body-tissue scan, the puncture needle12 is not perpendicular to the transmission/reception direction ofultrasonic waves in many cases. For this reason, in a needle-enhancedscan, the ultrasonic probe 11 transmits and receives ultrasonic waves inthe direction perpendicular to the puncture needle 12 such that strongerecho signals of the puncture needle 12 can be received (FIG. 5B). Animage in which only the puncture needle 12 is extracted can be acquiredby performing predetermined processing such as gain adjustment on echosignals acquired in the needle-enhanced scan.

As to the narrow-field needle-enhanced image and the wide-fieldneedle-enhanced image, images of corresponding plural steering angles(e.g., three angles of 15°, 30°, and) 45° may be acquired and one ofthese images in which the echo signal from the puncture needle 12 is thestrongest may be used as the narrow-field needle-enhanced image and awide-field needle-enhanced image. Additionally, the needle extractionprocessing is not limited to the aforementioned gain adjustment. Forinstance, time-sequential images may be acquired at the certain steeringangle in each acoustic field of the narrow-field needle-enhanced scanand the wide-field needle-enhanced scan, and the puncture needle 12 inmotion may be extracted based on motion vector between thesetime-sequential images.

FIG. 6A is a schematic diagram illustrating the narrow acoustic field 81in the narrow-field needle-enhanced scan, and FIG. 6B is a schematicdiagram illustrating the wide acoustic field 82 in the wide-fieldneedle-enhanced scan.

Since an ultrasonic beam is sufficiently focused in the narrow-fieldneedle-enhanced scan, a part of the puncture needle 12 positioned withinthe narrow acoustic field 81 is clearly depicted in the acquired image(as shown by the solid line in FIG. 6A), while echo signal cannot bereceived from a part of the puncture needle 12 positioned outside thenarrow acoustic field 81 (as shown by the two-dot chain line in FIG.6A).

In the wide-field needle-enhanced scan, though an echo signal can bereceived from any part of the puncture needle 12 positioned within thewide acoustic field 82, the image of the puncture needle 12 is blurredbecause the ultrasonic beam is not sufficiently focused (as shown by thebroken line in FIG. 6B). Incidentally, it is enough that the wideacoustic field 82 is wider in the elevation direction than the narrowacoustic field 81, the wide acoustic field 82 includes not only anacoustic field formed by narrowing effective (radiation) range of anultrasonic beam compared with the narrow acoustic field 81 but also anacoustic field formed by diffusing an ultrasonic beam.

FIG. 7 is a schematic diagram illustrating relationship between apuncture support image generated by combining a narrow-fieldneedle-enhanced image with a wide-field needle-enhanced image in theoff-plane state, the narrow acoustic field 81, and the wide acousticfield 82.

Since the part of the puncture needle 12 depicted in the narrow-fieldneedle-enhanced image is too small in the off-plane state, it isdifficult for a user to recognize the position of the puncture needle 12only from the narrow-field needle-enhanced image. For this reason, theimage generation function 62 of the present embodiment generates apuncture support image by combining the narrow-field needle-enhancedimage and the wide-field needle-enhanced image in the off-plane state.

Returning to FIG. 4, after generating the narrow-field needle-enhancedimage by performing the narrow-field needle-enhanced scan in the stepS2, in the step S3, the scan control function 61 determines whether ornot the wide-field needle-enhanced scan was performed in the lastexecuted procedure (the steps S1 to S12).

When the wide-field needle-enhanced scan was performed in the lastexecuted procedure (YES in step S3), and it was in the off-plane statein the last executed procedure (YES in step S4), then the processingproceeds to the step 5. In the step S5, the scan control function 61performs the wide-field needle-enhanced scan, and the image generationfunction 62 generates a wide-field needle-enhanced image based on dataacquired in this wide-field needle-enhanced scan. Additionally, whenperforming the wide-field needle-enhanced scan, the scan controlfunction 61 sets the timer threshold value Tth so as to activate thetimer 55 and cause the timer 55 to start time-count. When the timer 55has already been activated and is executing time-count, the scan controlfunction 61 resets the timer 55 and sets the timer threshold value Tthagain so as to cause the timer 55 to restart time-count. The time-countinformation of the timer 55 is used in the subsequent procedures to beexecuted after returning to the step S1 from the step S10.

In the next step S6, the image generation function 62 generates apuncture support image by combining the narrow-field needle-enhancedimage and the wide-field needle-enhanced image. In thisimage-composition processing, the image generation function 62 generatesthe puncture support image by prioritizing the narrow-fieldneedle-enhanced image over the wide-field needle-enhanced image.

In the next step S7, the state determination function 63 determineswhether or not the puncture needle 12 is displaced from the narrowacoustic field 81 being also an acoustic field of the body-tissue scan,i.e., whether or not it is in the off-plane state. Specifically, thestate determination function 63 determines to be in the off-plane statewhen the ratio, which is obtained by dividing the number of pixels ofthe narrow-field needle-enhanced image whose pixel values are not lessthan a predetermined pixel value by the number of pixels of thewide-field needle-enhanced image whose pixel values are not less than apredetermined pixel value, is lower than a predetermined ratio. Theabove-described predetermined pixel value may preferably be a pixelvalue whereby echo signals from body tissues can be eliminated and echosignals from the puncture needle 12 can be extracted. Additionally, asthe above-described predetermined ratio, a value within the range of 80%to 100% may preferably be used. The state determination function 63stores the information of the determination result of the step S7 in thememory circuitry 56 for example. When the state determination function63 determines that it is in the off-plane state, the processing proceedsto the step S8. Conversely, when the state determination function 63determines that it is not in the off-plane state, the processingproceeds to the step S9.

In the next step S8, the notification function 64 informs a user ofbeing in the off-plane state by causing the display 30 to displayinformation indicative of being in the off-plane state, causing anon-illustrated speaker to output voice indicative of being in theoff-plane state, or causing both of the display 30 and speaker to outputsuch information, or the like. Additionally, when the ultrasonic probe11 is a two-dimensional array probe, the state determination function 63can recognize the position of the puncture needle 12 with respect to thenarrow acoustic field 81. In order to resolve the off-plane state inthis case, the notification function 64 may preferably cause the display30 to display information on the translational direction and therotational direction in which the ultrasonic probe 11 should be moved,cause the speaker to output voice indicating the same information, orexecute both of them.

FIG. 8 is a schematic diagram illustrating a puncture support image anda composite image. In FIG. 8, a case where a B-mode image is used as abody-tissue image is illustrated.

In the next step S9, the image generation function 62 generates acomposite image by combining the body-tissue image and the puncturesupport image, and causes the display 30 to display the composite image(the bottom part of FIG. 8).

As shown in FIG. 7, the puncture needle 12 is sharply depicted in thenarrow-field needle-enhanced image, while being blurred and unclearlydepicted in the wide-field needle-enhanced image. Accordingly, a usercan easily recognize positional relationship between the puncture needle12 and acoustic fields including the narrow acoustic field 81 and thewide acoustic field 82 by confirming the puncture support imagegenerated by combining the narrow-field needle-enhanced image and thewide-field needle-enhanced image.

Thus, a user can easily position the puncture needle 12 within thenarrow acoustic field 81 thereby resolving the off-plane state byrotating the ultrasonic probe 11 such that the ratio of the wide-fieldneedle-enhanced image is reduced while watching the puncture supportimage. Further, a user can obtain a clear image of the puncture needle12 in paracentesis by resolving the off-plane state. Since a user canpierce the puncture needle 12 within a biological cross-section of thebody-tissue image by resolving the off-plane state, safety andreliability of medical treatment can be greatly improved.

Further, as shown in the left of the middle part of FIG. 8, the imagegeneration function 62 may preferably generate the puncture supportimage such that the part of the puncture needle 12 included in thewide-field needle-enhanced image and the rest of the puncture needle 12included in the narrow-field needle-enhanced image are different indisplay mode. For instance, in the puncture support image, the part ofthe puncture needle 12 included in the narrow-field needle-enhancedimage may be indicated by a dotted area, while the rest of the punctureneedle 12 included in the wide-field needle-enhanced image may beindicated by a hatched area.

In this case where the part of the puncture needle 12 included in thewide-field needle-enhanced image and the rest of the puncture needle 12included in the narrow-field needle-enhanced image are displayedtogether in the puncture support image in display modes different fromeach other, a user can more easily recognize positional relationshipbetween the puncture needle 12 and acoustic fields including the narrowacoustic field 81 and the wide acoustic field 82 by confirming thedisplay mode of the puncture needle 12. Accordingly, in this case, auser can easily recognize positional relationship between the punctureneedle 12 and the biological cross-section corresponding to thebody-tissue image by confirming the puncture support image.

Specifically, the image generation function 62 may preferably determinepixel values of respective pixels of the narrow-field needle-enhancedimage by using the same color map as the body-tissue image (e.g., acolor map in which color to be assigned to a pixel gradually changesfrom black to white in gray scale as a luminance value of the pixelincreases). Further, the image generation function 62 may preferablydetermine pixel values of respective pixels of the wide-fieldneedle-enhanced image by using a color map different from the color mapfor the narrow-field needle-enhanced image (e.g., a color map in whichcolor to be assigned to the pixel gradually changes from blue to red inchromatic color as a luminance value of the pixel increases). In thiscase, the higher the ratio of the wide-field needle-enhanced imagecombined in the puncture support image is (i.e., the more the punctureneedle 12 is displaced from the narrow acoustic field 81), the higherthe ratio of chromatic color in the puncture needle 12 becomes. Byassigning color to the pixels as described above, a user can more easilyrecognize positional relationship between the puncture needle 12 andacoustic fields including the narrow acoustic field 81 and the wideacoustic field 82. The image generation function 62 may cause thedisplay 30 to further display information indicating each meaning ofcolor maps for the narrow-field needle-enhanced image and the wide-fieldneedle-enhanced image.

Next, methods of generating the puncture support image implemented bythe image generation function 62 in the step S6 will be described inmore detail.

In the first method for generating the puncture support image such thatthe narrow-field needle-enhanced image is given priority over thewide-field needle-enhanced image, for each pixel a luminance value ofthe narrow-field needle-enhanced image and that of the wide-fieldneedle-enhanced image are compared, and the larger luminance value isused as a luminance value of corresponding pixel of the puncture supportimage.

The puncture needle 12 depicted in the narrow-field needle-enhancedimage is more in focus than the puncture needle 12 depicted in thewide-field needle-enhanced image. Accordingly, luminance values ofrespective pixels corresponding to the puncture needle 12 of thenarrow-field needle-enhanced image are considered to be generally higherthan luminance values of respective pixels corresponding to the punctureneedle 12 of the wide-field needle-enhanced image. Thus, the puncturesupport image can be generated by the first method in such a manner thatthe narrow-field needle-enhanced image is given priority over thewide-field needle-enhanced image.

In the second method, luminance values of at least one of thenarrow-field needle-enhanced image and the wide-field needle-enhancedimage are weighted, whereby the narrow-field needle-enhanced image isgiven priority over the wide-field needle-enhanced image. The secondmethod can be used in combination with the first method. Specifically,the narrow-field needle-enhanced image can be more surely given priorityby performing comparison of luminance values for each pixel between bothimages after weighting is performed on pixel values in such a mannerthat the narrow-field needle-enhanced image is more emphasized than thewide-field needle-enhanced image.

In the third method, higher transparence degree is assigned to thewide-field needle-enhanced image than to the narrow-fieldneedle-enhanced image, whereby the narrow-field needle-enhanced image isgiven priority over the wide-field needle-enhanced image in the puncturesupport image. Since the narrow-field needle-enhanced image becomeslower in transparence degree and higher in visibility than thewide-field needle-enhanced image in this case, the narrow-fieldneedle-enhanced image is given priority in the puncture support image.The third method can be used in combination with the first method andthe second method. For example, after performing weighting according tothe second method and assigning transparence degree according to thethird method, comparison of luminance degree is performed according tothe first method. Then, the part of the puncture needle 12 derived fromthe narrow-field needle-enhanced image is displayed with lowertransparence degree and higher luminance, while the rest of the punctureneedle 12 derived from the wide-field needle-enhanced image is displayedwith higher transparence degree and lower luminance.

The above-described first to third method can be applied even to theneedle-enhanced images that include remainder images of body tissues.

Further, when each of the narrow-field needle-enhanced image and thewide-field needle-enhanced image is such an image that only the punctureneedle 12 is extracted as a result of performing gain adjustment on echosignals, the fourth method in which the narrow-field needle-enhancedimage is superimposed on the wide-field needle-enhanced image may beused for generating the puncture support image. The fourth method can becombined with any of the above-described first to third methods, and allof those first to fourth methods can be combined with each other.

Those first to fourth methods can be applied to generation of acomposite image of a body-tissue image and puncture support image byreplacing the narrow-field needle-enhanced image with the body-tissueimage and replacing the wide-field needle-enhanced image with thepuncture support image.

Additionally, as to a method performed by the image generation function62 for generating the puncture support image, it is not limited to thefirst to fourth method, and any method can be applied in which thepuncture support image is generated such that the narrow-fieldneedle-enhanced image is given priority over the wide-fieldneedle-enhanced image.

Returning to FIG. 4, after displaying the composite image, the scancontrol function 61 determines whether ultrasonic scans should becompleted or not in the step S10. When it is determined that ultrasonicscans should not be finished, the processing returns to the step S1.Conversely, when it is determined that ultrasonic scans should befinished like a case where a command to complete ultrasonic scans isinputted by a user, the series of procedures is finished.

When the processing returns to the step S1 from the step S10, and whenthe wide-field needle-enhanced scan was not performed in the lastexecuted procedure of steps S1 to S12, then it is determined as NO inthe step 3, and the processing proceeds to the step S11.

Then, in the step S11, the scan control function 61 determines whetheror not a predetermined time has elapsed after the completion timing ofthe wide-field needle-enhanced scan performed last time. Specifically,the scan control function 61 determines whether or not the time-outsignal has outputted from the timer 55 to which the timer thresholdvalue Tth was set.

When the predetermined time has not elapsed from the completion timingof the wide-field needle-enhanced scan performed last time (NO at stepS11), the processing proceeds to the step S12. Further, even when thewide-field needle-enhanced scan was performed in the last executedprocedure of steps S1 to S12 and it is determined as YES in the step S3,the processing proceeds to the step S12 when it was not in the off-planestate in the last wide-field needle-enhanced scan and it is determinedas NO in the succeeding step S4. Then, in the step S12, the imagegeneration function 62 generates the puncture support image only fromthe narrow-field needle-enhanced image generated in the step S2 of thistime, and then the processing proceeds to the step S9 in which the imagegeneration function 62 generates a composite image. In this case,execution of the wide-field needle-enhanced scan is omitted. By omittingthe wide-field needle-enhanced scan, a frame rate for displayingcomposite images can be improved.

Meanwhile, when the predetermined time has elapsed after the completiontiming of the wide-field needle-enhanced scan performed last time (YESat step S11), the processing proceeds to the step S5 in which the scancontrol function 61 performs the wide-field needle-enhanced scan. Whenthe predetermined time has elapsed after the completion timing of thewide-field needle-enhanced scan performed last time, the predeterminedtime has also elapsed after the timing when the off-plane state isresolved. In this case, there is a possibility that the puncture needle12 is brought to the off-plane state again.

For this reason, when the predetermined time has elapsed from thecompletion timing of the wide-field needle-enhanced scan performed lasttime (YES at step S11), for checking whether it is in the off-planestate again or not, the wide-field needle-enhanced scan is performed(step S5), then a puncture support image is generated by combining thenarrow-field needle-enhanced image and the wide-field needle-enhancedimage (step S6), and then it is determined whether or not it is in theoff-plane state (step S7).

When it is determined as the off-plane state in the step S7, a user canimmediately recognize that the puncture needle 12 is positionallybrought to the off-plane state again with the help of the puncturesupport information outputted by the notification function 64 in stepS6, step S8. That is, a user can immediately recognize that it isbrought to the off-plane state, by being notified of informationindicative of being in the off-plane state outputted in the form ofvoice or a displayed image or confirming the puncture needle 12 that isderived from the wide-field needle-enhanced image and is depicted in thecomposite image.

Conversely, when the off-plane state is still resolved, steps S8 to S10are executed and the processing returns to the step S1 again. Then, inthe subsequent procedure, it is determined as YES in the step S3, and itis determined that it was not in the off-plane state in the step S4(i.e., it is determined that it was not in the off-plane state in thelast wide-field needle-enhanced scan), and then the processing proceedsto the step S12. Thus, when it is determined that the off-plane state isresolved, the frame rate can be recovered immediately from the nextcomposite-image generation processing by omitting the wide-fieldneedle-enhanced scan (step S5).

Although FIG. 4 shows an example of a procedure that includes output ofthe puncture support image (steps S6 and S12) and notification output ofinformation indicative of being in the off-plane state (step S8) as thepuncture support information, either the display output or thenotification output may be omitted.

Additionally, in the middle of the procedure of FIG. 4, the ultrasonicdiagnostic apparatus 10 may shift to the switching mode in which eitherone of the narrow-field needle-enhanced image and the wide-fieldneedle-enhanced image is displayed on the display 30, and may return tothe processing in FIG. 4 from the switching mode.

Even if the ultrasonic diagnostic apparatus 10 is in the switching mode,for instance, the following procedure can reduce the possibility that auser loses sight of the puncture needle 12. It is assumed that a doctorperforms paracentesis while confirming a composite image of anarrow-field needle-enhanced image and a body-tissue image. When it isbrought to the off-plane state which makes it difficult to confirm thepuncture needle 12 on the composite image, a user can switch images tobe displayed on the display 30 from a narrow-field needle-enhanced imageto a wide-field needle-enhanced image. For instance, a user can input acommand to switch images to be displayed on the display 30 via an inputcircuit such as a dial, a button, or the like provided on the ultrasonicprobe 11. In this manner, a user can easily keep sight of the punctureneedle 12 because the puncture needle 12 is reliably depicted in thewide-field needle-enhanced image. Additionally, a user can adjust theposition of the ultrasonic probe 11 on the basis of the wide-fieldneedle-enhanced image.

According to at least one of the above-described embodiments, theultrasonic diagnostic apparatus 10 can assist a user in easilyunderstanding positional relationship between the puncture needle 12 anda biological cross-section corresponding to a body-tissue image.

The processing circuitry 57 in the present embodiment is an example ofthe processing circuitry recited in the claims.

The term “processor” used in the explanation in the above-describedembodiments, for instance, refer to circuitry such as dedicated orgeneral purpose CPUs (Central Processing Units), dedicated orgeneral-purpose GPUs (Graphics Processing Units), or ASICs (ApplicationSpecific Integrated Circuits), programmable logic devices includingSPLDs (Simple Programmable Logic Devices), CPLDs (Complex ProgrammableLogic Devices), and FPGAs (Field Programmable Gate Arrays), and thelike. The processor implements various types of functions by reading outand executing programs stored in the memory circuitry.

In addition, instead of storing programs in the memory circuitry, theprograms may be directly incorporated into the circuitry of theprocessor. In this case, the processor implements each function byreading out and executing each program incorporated in its owncircuitry. Moreover, although in the above-described embodiments anexample is shown in which the processing circuitry configured of asingle processor implements every function, the processing circuitry maybe configured by combining plural processors independent of each otherso that each processor implements each function of the processingcircuitry by executing corresponding program. When a plurality ofprocessors are provided for the processing circuitry, the memory mediumfor storing programs may be individually provided for each processor, orone memory circuitry may collectively store programs corresponding toall the functions of the processors.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made without departing from the spiritof the inventions. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the inventions.

What is claimed is:
 1. An ultrasonic diagnostic apparatus comprising: atransmission/reception circuit configured to perform a first scan and asecond scan, which are different in acoustic field in an elevationdirection, by controlling at least one of transducers arranged along anazimuth direction and the elevation direction; and processing circuitryconfigured to generate a first needle-enhanced image by using dataacquired in the first scan, and generate a second needle-enhanced imageby using data acquired in the second scan.
 2. The ultrasonic diagnosticapparatus according to claim 1, wherein the processing circuitry isconfigured to output puncture support information based on the firstneedle-enhanced image and the second needle-enhanced image.
 3. Theultrasonic diagnostic apparatus according to claim 2, wherein theprocessing circuitry is configured to output voice or an imageindicating information to that effect as the puncture supportinformation by voice or display when a ratio, which is obtained bydividing a number of pixels of the first needle-enhanced image whosepixel values are equal to or higher than a predetermined pixel value bya number of pixels of the second needle-enhanced image whose pixelvalues are equal to or higher than the predetermined pixel value, islower than a predetermined ratio.
 4. The ultrasonic diagnostic apparatusaccording to claim 2, wherein the processing circuitry is configured togenerate a puncture support image as the puncture support information bycombining the first needle-enhanced image and the second needle-enhancedimage.
 5. The ultrasonic diagnostic apparatus according to claim 4,wherein the processing circuitry is configured to generate the puncturesupport image in such a manner that an image of a puncture needleincluded in the first needle-enhanced image and an image of the punctureneedle included in the second needle-enhanced image are different indisplay mode.
 6. The ultrasonic diagnostic apparatus according to claim5, wherein: the transmission/reception circuit is configured to performthe first scan and the second scan in such a manner that a width of anacoustic field in the elevation direction in the second scan is widerthan a width of an acoustic field in the elevation direction in thefirst scan; and the processing circuitry is configured to generate thepuncture support image so as to give priority to the firstneedle-enhanced image over the second needle-enhanced image.
 7. Theultrasonic diagnostic apparatus according to claim 6, wherein theprocessing circuitry is configured to compare for each pixel a luminancevalue of the first needle-enhanced image and a luminance value of thesecond needle-enhanced image, and generate the puncture support imagesuch that the larger luminance value is used as a luminance value ofcorresponding pixel of the puncture support image.
 8. The ultrasonicdiagnostic apparatus according to claim 6, wherein the processingcircuitry is configured to weight luminance values of at least one ofthe first needle-enhanced image and the second needle-enhanced image insuch a manner that the first needle-enhanced image is given priorityover the second needle-enhanced image.
 9. The ultrasonic diagnosticapparatus according to claim 6, wherein the processing circuitry isconfigured to assign higher transparence degree to the secondneedle-enhanced image than to the first needle-enhanced image in such amanner that the first needle-enhanced image is given priority over thesecond needle-enhanced image.
 10. The ultrasonic diagnostic apparatusaccording to claim 6, wherein the processing circuitry is configured togenerate the first needle-enhanced image by extracting only an imagedata corresponding to a puncture needle from the data acquired in thefirst scan, generate the second needle-enhanced image by extracting onlyan image data corresponding to the puncture needle from the dataacquired in the second scan, and generate the puncture support image insuch a manner that the first needle-enhanced image is superimposed onthe second needle-enhanced image.
 11. The ultrasonic diagnosticapparatus according to claim 4, wherein the processing circuitry isconfigured to control the transmission/reception circuit such that thetransmission/reception circuit omits execution of the second scan when aratio, which is obtained by dividing a number of pixels of the firstneedle-enhanced image whose pixel values are equal to or higher than apredetermined pixel value by a number of pixels of the secondneedle-enhanced image whose pixel values are equal to or higher than apredetermined pixel value, is not lower than a predetermined ratio, andgenerate the puncture support image from the first needle-enhanced imagewhen the execution of the second scan is omitted.
 12. The ultrasonicdiagnostic apparatus according to claim 11, wherein the processingcircuitry is configured to control the transmission/reception circuitsuch that the transmission/reception circuit resumes execution of thesecond scan when a predetermined time elapses after omission of theexecution of the second scan or when an instruction to resume theexecution of the second scan is inputted via an input circuit by a user,and generate the puncture support image by combining the firstneedle-enhanced image and the second needle-enhanced image when theexecution of the second scan is resumed.
 13. The ultrasonic diagnosticapparatus according to claim 4, Wherein: the transmission/receptioncircuit is configured to perform a third scan for generating abody-tissue image of an object; and the processing circuitry isconfigured to generate the body-tissue image by using data acquired inthe third scan, and generate a composite image of the puncture supportimage and the body-tissue image.
 14. The ultrasonic diagnostic apparatusaccording to claim 13, wherein a width of an acoustic field in theelevation direction in the third scan is substantially equal to anarrower one of a width of an acoustic field in the elevation directionin the first scan and a width of an acoustic field in the elevationdirection in the second scan.
 15. The ultrasonic diagnostic apparatusaccording to claim 13, wherein the third scan is a B-mode scan.
 16. Theultrasonic diagnostic apparatus according to claim 13, wherein theprocessing circuitry is configured to determine pixel values of thebody-tissue image and pixel values of the first needle-enhanced image byusing a first color map, and determine pixel values of the secondneedle-enhanced image by using a second color map different from thefirst color map.
 17. The ultrasonic diagnostic apparatus according toclaim 1, wherein the processing circuitry is configured to cause adisplay to display one of the first needle-enhanced image and the secondneedle-enhanced image, and switch an image displayed on the display fromone of the first needle-enhanced image and the second needle-enhancedimage to another in an automatic manner according to setting or in amanual manner according to an instruction from a user.
 18. Theultrasonic diagnostic apparatus according to claim 1, wherein theprocessing circuitry is configured to cause a display to display agenerated image.
 19. The ultrasonic diagnostic apparatus according toclaim 1, further comprising an ultrasonic probe equipped with pluraltransducers arranged along the azimuth direction and the elevationdirection, wherein the ultrasonic probe is configured, by beingcontrolled by the processing circuitry, to be capable of generatingacoustic fields each of which has a different width in the elevationdirection and is symmetric about a center axis along the elevationdirection.
 20. An ultrasonic image generation method comprising:performing a first scan and a second scan, which are different inacoustic field in an elevation direction, by controlling at least one oftransducers arranged along an azimuth direction and the elevationdirection; generating a first needle-enhanced image by using dataacquired in the first scan; and generating a second needle-enhancedimage by using data acquired in the second scan.